Subject: Re: [geometry] 3D Coordinate Systems types - right-handed vs left-handed (and confusing rotate_transform)
From: Adam Wulkiewicz (adam.wulkiewicz_at_[hidden])
Date: 2015-10-08 16:23:44
Hussein Almashouq wrote:
> Hi to all,
> I wonder is how boost geometry models 3d points and boxes using
> which 3D coordinate systems convention Left or Right-handed ?
From the user's perspective I think this shouldn't be important. I may
be missing something but I think that currently in Boost.Geometry the
only place where this could be noticeable is transform() with
rotate_transformer. It only supports 2D case though.
What exactly would you like to do with Points and Boxes?
Internally in the library we're calculating e.g. cross products in some
cases, for instance in spherical side formula, there is also also
cross_product() function in extensions. Therefore I always thought that
internally we're using right-handed coordinate system, with angles
increasing counter-clockwise. Surprisingly the rotate_transformer
rotates geometries clockwise. It's even more confusing because in the
comment there is a link to the wikipedia page and there the
counter-clockwise rotation is presented. Am I missing something? Why was
rotate_transformer implemented this way?
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